1. Field of the Invention
The present invention relates to communication service, and more particularly, to a method and apparatus that updates and provides presence information.
2. Description of the Related Art
In general, a presence service refers to a service that provides presence information of a user to other users in order to identify the user's states, for example, a physical location, a communication state, communication media, etc. Presentity refers to a user, i.e., an entity that provides presence information. Watcher refers to the other user, i.e., an entity that requests presence information about a presentity. Watchers can identify a change in the presence information of presentities through the presence service.
In the presence service, presence information is formed by simply combining data about a state of a presentity. Examples of the state of a presentity are a physical location, a communication state, communication media, etc. Watchers can individually identify a physical location, a communication state, communication media, etc. of a presentity, through presence information. Watchers, however, have difficulty clearly and specifically identifying the states of a presentity from presence information. Therefore, a presence service is needed to provide presence information with a more complex structure.